Bioreactors used for growing cells and organisms need frequent monitoring of the nutrient media to adjust its characteristics to optimize growth. Most commonly it is done by sampling the nutrient media through a port in the bioreactor, which carries the risk of contaminating the bioreactor; also used is the method of routing the nutrient media through a flow cell, which still contains the risk of contamination. More recently, the monitoring has been done by using disposable sensors, which are installed inside a bioreactor and reading their responses from outside the bag; while this method offers a practical choice, it remains less desirable due to its high variability of responses and the high cost of using this method.
There remains an unmet need to create a method for directly monitoring the characteristics of the nutrient media in a bioreactor without removing the nutrient media from the bioreactor to record such parameters as pH, optical density, cell count, dissolved oxygen, dissolved carbon dioxide, glucose concentration and other specific parameters for which a detector is available.
The present invention allows placement of emitter probes of electromagnetic or sound waves inside a bioreactor without contacting the nutrient media and also places a detector of electromagnetic or sound waves inside the bioreactor without contacting the nutrient media. Disposable receptacles receptacle the emitter probe and detector probes are fully transparent to the chosen radiation or wave type employed. The distance between the emitter probe and the detector probe are adjusted by positioning these at different heights when using a V-shaped receptacle or by installing them apart at a pre-determined distance inside a bioreactor. The nutrient media between the transmitter and detector serves as the tested sample.
The angle of probes determines whether the measured radiation is transmitted or diffracted; when facing, the measurement is of transmitted radiation and when placed at an angle such that the path of the line of sight of the probes crosses, measured radiation is diffracted radiation.
The method of present invention involves installing a receptacle inside a disposable bioreactor such that the receptacles for emitter probes and detectors are accessible from outside; the receptacle can also be used in non-disposable bioreactors.
The present invention offers a cost-effective solution to monitoring bioreactors since the expensive emitter probes and detectors are re-used and only the receptacle that houses them is disposed after a single use.